Appliances that include a cooktop such as coil cooktops or gas cooktops transfer a significant amount of energy to heat a cooking vessel such as a pan or pot and its contents.
A major concern regarding cooktops is the potential for a fire. In particular, the continuous or semi-continuous application of energy to the vessel can cause the vessel and/or its contents to ignite or otherwise catch fire.
For example, one of the most common causes of a cooktop fire is for the temperature of an inside surface of a cooking vessel to exceed ignition temperatures associated with one or more oils or other lipids in the cooking vessel. Another common cause of cooktop fires results from an increase in vessel temperature when liquids in the vessel are completely evaporated, a condition referred to as “boil-dry.” Therefore, liquids are no longer present in the vessel to moderate temperature and other materials may be heated to an ignition temperature.
In addition, due to the presence of accelerants, operator inattention, or other factors, a kitchen fire can quickly expand beyond the control of the operator, causing major home damage and/or imperiling human life. As such, knowledge of the temperature of the cooking vessel would be helpful for preventing cooktop fires.
However, due to the non-identical shapes and sizes of cooking vessels, it is difficult for currently existing sensors to obtain an accurate reading of vessel temperature. For example, certain existing sensor assemblies may be unable to maintain sufficient contact with the cooking vessel as it is shifted about the cooktop or due to vessel shape anomalies such as embossed features, warping, or roughness.
Furthermore, certain existing cooktop control algorithms can fail to avoid or account for certain scenarios where ignition of oils or lipids is highly likely. In particular, most existing control algorithms focus on moderating cooktop/vessel temperature once the cooktop/vessel has reached a steady state (e.g. during the cooking period after initial heat up). However, these control algorithms can fail to provide proper moderation during the initial heat up and therefore may be susceptible to initial temperature overshoot, a common cause of cooktop fires.
As an example, certain existing controls rely upon the application of a current to a bi-metal strip which heats and cools to generate a duty cycle. While this control method may provide suitable control during steady state, it fails to address initial temperature overshoot, thereby rendering the cooktop susceptible to cooktop fires.
Therefore, cooktop temperature assemblies that can obtain an accurate temperature reading for the cooktop or vessel are desirable. Furthermore, cooktop control algorithms which reduce the potential for cooktop fires in both initial heat up and steady state are desirable.